ARRT Computed Tomography (CT) Certification Examination — Questions and Answers

Question 1: Which premedication regimen is most commonly recommended for elective contrast administration in patients with a prior mild allergic-like contrast reaction?

IV epinephrine 30 minutes before contrast
Oral prednisone 50 mg at 13, 7, and 1 hour before contrast plus diphenhydramine 50 mg 1 hour before (Correct answer)
No premedication is needed for mild prior reactions
IV methylprednisolone only, given 1 minute before injection

Correct answer: Oral prednisone 50 mg at 13, 7, and 1 hour before contrast plus diphenhydramine 50 mg 1 hour before

The ACR-recommended premedication protocol for non-emergent cases includes oral prednisone at 13, 7, and 1 hour before contrast plus diphenhydramine 50 mg 1 hour before.

Question 2: A CT head without contrast shows a hyperdense crescent-shaped collection along the inner table of the skull. This is most consistent with:

Subarachnoid hemorrhage
Intraparenchymal hematoma
Acute subdural hematoma (Correct answer)
Epidural hematoma

Correct answer: Acute subdural hematoma

Acute subdural hematomas appear as hyperdense crescent-shaped collections that conform to the brain surface and cross suture lines.

Question 3: What is preventive maintenance?

Regular scheduled maintenance to prevent equipment failure (Correct answer)
Fixing equipment after it breaks
Cleaning only
Replacing all equipment annually

Correct answer: Regular scheduled maintenance to prevent equipment failure

Preventive maintenance involves regular, scheduled inspections and servicing to prevent unexpected breakdowns and extend equipment life.

Question 4: A technologist holds ARRT primary certification in Radiography and a post-primary in CT. How many total CE credits are required per cycle?

24 total, shared across both credentials (Correct answer)
36 total — 24 for primary plus 12 for post-primary
48 total — 24 for each credential separately
24 total, with at least 6 specific to CT

Correct answer: 24 total, shared across both credentials

ARRT allows the same 24 Category A CE credits to satisfy renewal requirements for both the primary and post-primary certifications simultaneously.

Question 5: On axial CT of the orbit, which extraocular muscle is located at the medial wall of the orbit?

Superior rectus
Superior oblique
Inferior oblique
Medial rectus (Correct answer)

Correct answer: Medial rectus

The medial rectus muscle runs along the medial orbital wall and is the most commonly enlarged muscle in thyroid eye disease.

Question 6: A CT technologist completes 30 Category A credits in one renewal cycle. How many, if any, credits can be carried over to the next cycle?

0 credits — no carryover is allowed (Correct answer)
All excess credits carry over automatically
6 credits can be carried over
12 credits can be carried over

Correct answer: 0 credits — no carryover is allowed

ARRT does not allow Category A CE credits to be carried over from one renewal cycle to the next.

Question 7: The pitch value in helical CT is defined as:

Slice thickness divided by detector row width
Table travel per rotation divided by total beam collimation width (Correct answer)
Gantry rotation speed divided by table speed
kVp divided by mA

Correct answer: Table travel per rotation divided by total beam collimation width

Pitch = table distance traveled per 360° rotation ÷ total collimated beam width, and values >1 indicate gaps in data coverage.

Question 8: A CT image shows ring artifacts. The MOST likely cause is:

Patient motion during scanning
A malfunctioning or miscalibrated detector element (Correct answer)
Too low an mAs setting
Incorrect kVp selection

Correct answer: A malfunctioning or miscalibrated detector element

Ring artifacts appear as circular bands centered on the isocenter and are caused by a single detector element producing consistently incorrect readings.

Question 9: Which type of isolation precaution is used for patients with pulmonary tuberculosis?

Airborne precautions (Correct answer)
Reverse isolation
Contact precautions
Droplet precautions

Correct answer: Airborne precautions

Pulmonary tuberculosis is spread by airborne particles (droplet nuclei <5 µm) requiring airborne precautions including N95 respirator use and negative-pressure rooms.

Question 10: The spatial frequency at which the MTF falls to 10% is commonly used to define:

The limiting spatial resolution of the CT system (Correct answer)
The optimal reconstruction FOV
The detective quantum efficiency (DQE)
The noise power spectrum peak

Correct answer: The limiting spatial resolution of the CT system

MTF10% represents the highest spatial frequency the system can transfer with 10% modulation, effectively defining the limiting resolution.

Question 11: To troubleshoot a CT image showing significant noise (grainy appearance), the technologist should first consider adjusting which parameter?

Increasing pitch
Decreasing kVp
Increasing mAs (Correct answer)
Reducing matrix size

Correct answer: Increasing mAs

Increasing mAs raises the number of X-ray photons, directly reducing quantum noise and improving signal-to-noise ratio.

Question 12: Multiplanar reformation (MPR) in CT refers to:

Reconstructing axial images into coronal, sagittal, or oblique planes (Correct answer)
Applying color to CT images based on Hounsfield units
Subtracting pre-contrast from post-contrast images
Generating 3D surface models from volumetric data

Correct answer: Reconstructing axial images into coronal, sagittal, or oblique planes

MPR uses the volumetric CT dataset to create reformatted images in any anatomical plane without additional radiation exposure to the patient.

Question 13: When creating coronal MPR images from a helical chest CT, image quality is best when the original acquisition used:

Large FOV and minimal overlap
Thin slices (≤1 mm) reconstructed at overlapping intervals (0.5–0.7 mm) (Correct answer)
High pitch with standard soft tissue kernel only
Thick slices (5–10 mm) reconstructed at 5 mm intervals

Correct answer: Thin slices (≤1 mm) reconstructed at overlapping intervals (0.5–0.7 mm)

Thin, overlapping reconstructions produce near-isotropic voxels that allow high-quality coronal and sagittal reformations without visible stair-step artifacts.

Question 14: Which statement best describes the ARRT's reciprocity or equivalency policy for CT candidates credentialed by a foreign radiologic technology body?

Foreign credentials are not automatically accepted; candidates must meet ARRT eligibility requirements independently (Correct answer)
Foreign credentials qualify candidates for an expedited review process
Foreign credentials are fully accepted without additional review
Foreign-credentialed technologists are exempt from the CT examination

Correct answer: Foreign credentials are not automatically accepted; candidates must meet ARRT eligibility requirements independently

ARRT does not grant automatic reciprocity for foreign credentials; each candidate must independently satisfy ARRT eligibility criteria.

Question 15: A CT technologist completes a 3-credit online module from an ARRT-approved sponsor. How should this be recorded?

Only if the module includes a hands-on component
As Category B self-study credit
It counts only if completed before the renewal year begins
As 3 Category A CE credits (Correct answer)

Correct answer: As 3 Category A CE credits

Online modules from ARRT-approved sponsors qualify as Category A CE credits and count toward the 24-credit renewal requirement.

Question 16: On a sagittal CT reconstruction of the chest, the azygos vein is best identified by its arch over which structure?

The right main bronchus (Correct answer)
The superior vena cava
The right pulmonary artery
The left main bronchus

Correct answer: The right main bronchus

The azygos vein arches over the right main bronchus before draining into the posterior superior vena cava.

Question 17: Which of the following patient populations has the HIGHEST radiosensitivity?

Adult males aged 40-60
Fetuses and children under 5 years of age (Correct answer)
Elderly patients over 75
Pregnant women in the third trimester

Correct answer: Fetuses and children under 5 years of age

Fetuses and young children are most radiosensitive due to rapidly dividing cells and longer life expectancy over which stochastic effects can manifest.

Question 18: Which of the following is the correct action if a detector ring artifact is identified during a quality control check of the CT scanner?

Continue scanning and note in the patient report
Recalibrate the detector and notify the medical physicist (Correct answer)
Increase mAs to compensate
Decrease the FOV

Correct answer: Recalibrate the detector and notify the medical physicist

A ring artifact indicates a detector calibration issue that must be corrected by recalibration or service; the medical physicist should be notified per QC protocols.

Question 19: What is the window level and window width on CT images?

Scan speed controls
Patient positioning parameters
Physical measurements of the CT scanner
Settings that control the brightness and contrast of displayed images (Correct answer)

Correct answer: Settings that control the brightness and contrast of displayed images

Window level sets the center brightness (what HU appears as middle gray) and window width controls contrast range (how many HUs span from black to white).

Question 20: Increasing the CT reconstruction matrix from 512×512 to 1024×1024 while keeping FOV constant will:

Increase pixel size and reduce spatial resolution
Decrease pixel size and potentially improve spatial resolution (Correct answer)
Reduce scan time
Decrease image noise

Correct answer: Decrease pixel size and potentially improve spatial resolution

Doubling the matrix halves the pixel size (FOV/matrix), which can improve displayed spatial resolution but also increases image noise and data storage requirements.

Question 21: On CT spine, which finding is most consistent with a herniated nucleus pulposus at L4-L5 causing left leg radiculopathy?

Central disc bulge at L3-L4
Left foraminal stenosis at L3-L4
Right paracentral disc protrusion compressing the L4 nerve root in the lateral recess
Left paracentral disc extrusion compressing the left L5 nerve root (Correct answer)

Correct answer: Left paracentral disc extrusion compressing the left L5 nerve root

A left paracentral extrusion at L4-L5 compresses the traversing L5 nerve root in the lateral recess, causing ipsilateral radiculopathy.

Question 22: Which vital sign finding in an adult patient should be reported to the supervising clinician before proceeding with a routine radiographic exam?

Respiratory rate of 10 breaths per minute (Correct answer)
Pulse of 72 beats per minute
Temperature of 98.6°F (37°C)
Blood pressure of 118/76 mmHg

Correct answer: Respiratory rate of 10 breaths per minute

A respiratory rate of 10 breaths per minute is below the normal range (12-20) and indicates bradypnea, which warrants clinical notification.

Question 23: A 55-year-old patient develops generalized urticaria approximately 5 minutes after IV contrast injection. This reaction is best classified as:

A physiologic reaction due to contrast osmolality
A severe anaphylactic reaction requiring epinephrine
A mild acute allergic-like (anaphylactoid) reaction (Correct answer)
A delayed hypersensitivity reaction

Correct answer: A mild acute allergic-like (anaphylactoid) reaction

Generalized urticaria without systemic involvement (no bronchospasm or hypotension) represents a mild acute allergic-like reaction, typically treated with antihistamines.

Question 24: When a CT scanner undergoes a tube replacement, which quality control step is mandatory before returning the unit to clinical service?

Gantry tilt angle verification only
Low-contrast detectability test only
Full calibration and acceptance testing (Correct answer)
Slice sensitivity profile measurement only

Correct answer: Full calibration and acceptance testing

After a major component replacement such as an X-ray tube, full calibration and acceptance testing must be performed to ensure the scanner meets all performance specifications.

Question 25: Which of the following best explains why ARRT periodically revises its CT examination content specifications?

To satisfy JRCERT annual audit requirements
To match content used by competing certification bodies
To increase examination difficulty and reduce pass rates
To align the examination with evolving clinical practice identified through practice analysis (Correct answer)

Correct answer: To align the examination with evolving clinical practice identified through practice analysis

ARRT updates content specifications based on practice analysis data to ensure examinations reflect what entry-level technologists actually need to know in current clinical settings.

Question 26: In CT, contrast-to-noise ratio (CNR) is BEST described as:

The ratio of signal to detector dark current
The number of line pairs per centimeter resolved
The ability to detect objects of varying sizes
The difference in HU between two structures divided by image noise (Correct answer)

Correct answer: The difference in HU between two structures divided by image noise

CNR = (HU_structure − HU_background) ÷ noise standard deviation, quantifying how well a structure stands out against background noise.

Question 27: Which of the following is required as proof of identity when a candidate checks in for the ARRT CT examination?

Government-issued photo ID with signature (Correct answer)
Employer-issued badge
Social Security card
ARRT membership card only

Correct answer: Government-issued photo ID with signature

Pearson VUE and ARRT require a valid, unexpired government-issued photo ID with a matching signature at check-in.

Question 28: Which type of CT detector material is most commonly used in modern multi-detector CT (MDCT) systems due to its high conversion efficiency and fast decay time?

Bismuth germanate (BGO) crystals
Sodium iodide (NaI) crystal detectors
Xenon gas ionization chambers
Gadolinium oxysulfide (GOS) solid-state scintillators (Correct answer)

Correct answer: Gadolinium oxysulfide (GOS) solid-state scintillators

Modern MDCT scanners predominantly use solid-state scintillator detectors such as gadolinium oxysulfide because of their high X-ray absorption efficiency and rapid afterglow decay.

Question 29: What is the first priority in any emergency situation?

Contact the media
Ensure the safety of all personnel (Correct answer)
Save equipment
Write a report

Correct answer: Ensure the safety of all personnel

In any emergency, the first priority is always the safety and well-being of all personnel. Equipment and materials can be replaced; lives cannot.

Question 30: Which of the following is a prerequisite for pursuing ARRT Computed Tomography certification?

At least five years of experience in radiologic technology
Completion of 40 hours of CT-specific continuing education
Holding an ARRT certification in radiography, nuclear medicine, or radiation therapy (Correct answer)
Bachelor’s degree in radiologic sciences

Correct answer: Holding an ARRT certification in radiography, nuclear medicine, or radiation therapy

The ARRT Computed Tomography (CT) certification is a post-primary certification, meaning candidates must first hold a primary ARRT certification. Specifically, one must be certified in radiography (R), nuclear medicine technology (N), or radiation therapy (T) to be eligible to pursue the CT certification. This ensures a foundational understanding of radiologic principles before specializing.

Question 31: On CT of the head, lenticular (biconvex) hyperdensity is identified adjacent to the temporal bone. What is the most likely cause?

Hypertensive hemorrhage
Middle meningeal artery rupture causing epidural hematoma (Correct answer)
Berry aneurysm rupture
Bridging vein rupture causing subdural hematoma

Correct answer: Middle meningeal artery rupture causing epidural hematoma

Epidural hematomas result from middle meningeal artery injury and form a biconvex hyperdense collection limited by dural attachments at sutures.

Question 32: An employer lists 'ARRT(CT)' as a preferred qualification in a job posting. What does this abbreviation signify?

Certification by the American College of Tomography
ARRT registered with CT post-primary certification (Correct answer)
The applicant holds a general radiology license only
Completion of a CT vendor-specific training course

Correct answer: ARRT registered with CT post-primary certification

ARRT(CT) denotes that an individual holds ARRT registration and has passed the CT post-primary certification examination.

Question 33: A CT abdomen in a trauma patient shows high-density fluid in the hepatorenal space (Morison's pouch). What does this indicate?

Hemoperitoneum (Correct answer)
Lymphocele
Physiologic peritoneal fluid
Biliary leak

Correct answer: Hemoperitoneum

High-attenuation free fluid (>30 HU) in Morison's pouch following trauma indicates hemoperitoneum from solid organ or vascular injury.

Question 34: Cupping artifact on a CT image of a large cylindrical phantom most likely indicates:

Beam hardening due to preferential absorption of lower-energy photons (Correct answer)
Excessive pitch value
Patient motion during scanning
Incorrect detector gain calibration

Correct answer: Beam hardening due to preferential absorption of lower-energy photons

Cupping artifact occurs because low-energy photons are preferentially absorbed by the periphery, hardening the beam and making the center appear falsely darker.

Question 35: Which of the following primary credentials does NOT qualify a technologist to sit for the ARRT CT post-primary examination?

Nuclear Medicine Technology (N)
Chiropractic (DACBR) (Correct answer)
Radiography (R)
Radiation Therapy (T)

Correct answer: Chiropractic (DACBR)

Chiropractic radiology is not an ARRT-recognized qualifying primary pathway for CT post-primary eligibility.

Question 36: When treating a severe anaphylactic reaction to contrast media in an adult patient, what is the first-line drug and route of administration?

Epinephrine 0.3 mg (1:1000) intramuscular injection into the anterolateral thigh (Correct answer)
Atropine 1 mg IV push
Methylprednisolone 125 mg IV bolus
Diphenhydramine 50 mg IV

Correct answer: Epinephrine 0.3 mg (1:1000) intramuscular injection into the anterolateral thigh

Epinephrine 0.3 mg of 1:1000 concentration given IM into the anterolateral thigh is the first-line treatment for severe anaphylaxis due to its rapid absorption and alpha/beta adrenergic effects.

Question 37: How many total attempts does ARRT allow a candidate to take the CT certification examination?

Unlimited attempts
5 attempts
3 attempts (Correct answer)
2 attempts

Correct answer: 3 attempts

ARRT limits candidates to 3 total attempts to pass each post-primary examination, including CT.

Question 38: Which CT image quality parameter is measured using a modulation transfer function (MTF)?

Noise power spectrum
Contrast resolution
Spatial resolution (Correct answer)
Temporal resolution

Correct answer: Spatial resolution

The MTF quantifies spatial resolution by describing how faithfully the CT system reproduces objects of varying spatial frequencies.

Question 39: In CT angiography post-processing, bone subtraction is performed primarily to:

Remove iodine signal from vessels
Reduce noise in the image
Eliminate overlying bone to improve visualization of adjacent vessels (Correct answer)
Correct for beam hardening

Correct answer: Eliminate overlying bone to improve visualization of adjacent vessels

Bone subtraction algorithms register and subtract non-contrast images from contrast-enhanced images, removing osseous structures that would otherwise obscure adjacent vessels.

Question 40: In a CT scan of the abdomen and pelvis with oral contrast, positive oral contrast (barium or iodine-based) is used primarily to:

Reduce radiation dose
Improve bone visualization
Improve arterial phase timing
Distinguish bowel loops from adjacent masses (Correct answer)

Correct answer: Distinguish bowel loops from adjacent masses

Positive oral contrast opacifies bowel loops so they can be easily distinguished from adjacent lymph nodes, vessels, or pathological masses.

Question 41: Stochastic effects of radiation are characterized by which of the following?

Occurring only in radiosensitive tissues such as bone marrow
No dose threshold; probability of occurrence increases with dose (Correct answer)
A threshold dose below which the effect cannot occur
Severity increasing proportionally with dose above the threshold

Correct answer: No dose threshold; probability of occurrence increases with dose

Stochastic effects (e.g., radiation-induced cancer) are assumed to have no threshold; their probability, not severity, increases with dose.

Question 42: What documentation does an ARRT candidate typically need to submit to verify clinical competency in CT?

Employer payroll records
Competency verification signed by a supervising radiologist or qualified technologist (Correct answer)
ACR accreditation certificate of the facility
A letter from the state radiology board

Correct answer: Competency verification signed by a supervising radiologist or qualified technologist

Clinical competency must be verified by a supervising qualified professional who can attest that the candidate performed required procedures.

Question 43: Which of the following is NOT an acceptable method for documenting completed CE credits with ARRT?

Online entry through the ARRT website
Verbal confirmation from a supervisor (Correct answer)
Having the approved sponsor report credits to ARRT directly
Submitting certificates directly to ARRT upon renewal

Correct answer: Verbal confirmation from a supervisor

ARRT requires verifiable documentation of CE credits; verbal confirmation from a supervisor is not an accepted method.

Question 44: To meet ARRT’s ethics requirements, which of the following is necessary?

Pass a background check and provide character references
Agree to follow the ARRT Standards of Ethics and report any potential violations (Correct answer)
Take a separate ethics exam during the certification process
Submit a personal statement of professional ethics

Correct answer: Agree to follow the ARRT Standards of Ethics and report any potential violations

The ARRT places a strong emphasis on ethical conduct within the radiologic technology profession. To meet their ethics requirements, candidates must formally agree to adhere to the ARRT Standards of Ethics, which outline professional responsibilities and conduct. This commitment includes reporting any potential violations, upholding the integrity of the profession.

Question 45: The ARRT Standards of Ethics is incorporated into the CT certification process primarily to:

Verify candidates' financial standing
Assess candidates' academic GPA
Ensure candidates demonstrate professional integrity and moral character (Correct answer)
Confirm candidates' insurance coverage

Correct answer: Ensure candidates demonstrate professional integrity and moral character

The Standards of Ethics screening ensures that only individuals with demonstrated professional integrity are certified.

Question 46: What is the role of the ARRT Board of Trustees in the accreditation and credentialing process?

They govern ARRT policy, including eligibility requirements and ethical standards (Correct answer)
They perform on-site inspections of clinical training sites
They directly score individual certification examinations
They issue state radiologic technology licenses

Correct answer: They govern ARRT policy, including eligibility requirements and ethical standards

The ARRT Board of Trustees is the governing body responsible for setting policy, eligibility criteria, and ethical standards for the organization.

Question 47: Which of the following best describes 'overranging' (z-overscanning) in helical CT?

Using a higher kVp than needed
Extra rotations acquired beyond the requested scan range to complete helical reconstruction (Correct answer)
Applying too wide a display window
Scanning beyond the prescribed FOV diameter

Correct answer: Extra rotations acquired beyond the requested scan range to complete helical reconstruction

Overranging refers to the additional tube rotations at the start and end of a helical scan needed to reconstruct the first and last requested slices, increasing dose.

Question 48: What is the function of epithelial tissue?

To store fat
To cover body surfaces, line cavities, and form glands (Correct answer)
To contract and produce movement
To transmit electrical signals

Correct answer: To cover body surfaces, line cavities, and form glands

Epithelial tissue covers all body surfaces, lines body cavities and organs, and forms glands. It provides protection, absorption, secretion, and sensation.

Question 49: How long is the ARRT CT post-primary certification credential valid before renewal is required?

5 years
2 years (biennium) (Correct answer)
Lifetime with no renewal
1 year

Correct answer: 2 years (biennium)

Like all ARRT credentials, CT post-primary certification must be renewed every two years through the biennial renewal process.

Question 50: What is homeostasis?

An organ system
A type of cell division
The body's ability to maintain stable internal conditions (Correct answer)
A disease state

Correct answer: The body's ability to maintain stable internal conditions

Homeostasis is the body's dynamic process of maintaining stable internal conditions (temperature, pH, blood sugar) despite external changes.

Question 51: Which organization is primarily responsible for accrediting radiologic technology programs in the United States?

JRCERT (Correct answer)
ARRT
ACR
ACR-AAPM

Correct answer: JRCERT

The Joint Review Committee on Education in Radiologic Technology (JRCERT) is the primary accrediting body for radiologic technology programs.

Question 52: A CT myelography protocol requires which patient preparation step unique to this exam?

Intrathecal injection of iodinated contrast (Correct answer)
Oral bowel prep the night before
Fasting for 6 hours prior
IV injection of gadolinium contrast

Correct answer: Intrathecal injection of iodinated contrast

CT myelography requires intrathecal (subarachnoid) injection of water-soluble iodinated contrast to opacify the spinal canal.

Question 53: Which regulatory body sets the annual occupational effective dose limit of 50 mSv in the United States?

CDC
NRC and Agreement States (Correct answer)
FDA
ARRT

Correct answer: NRC and Agreement States

The Nuclear Regulatory Commission (NRC) and Agreement State regulations set the 50 mSv/year occupational effective dose limit (10 CFR 20).

Question 54: How does ARRT CT certification influence a technologist's ability to work at facilities affiliated with academic medical centers?

It is disqualifying because academic centers prefer non-certified staff
It is irrelevant because academic centers set their own competency standards independently of ARRT
Academic medical centers often require specialty certifications for positions involving advanced imaging modalities (Correct answer)
It only matters for technologists who also teach radiology students

Correct answer: Academic medical centers often require specialty certifications for positions involving advanced imaging modalities

Academic medical centers frequently list specialty ARRT certifications as required or preferred qualifications for CT positions due to their high-acuity patient populations.

Question 55: What does CT stand for in medical imaging?

Clinical Therapy
Cardiac Testing
Computed Tomography (Correct answer)
Central Treatment

Correct answer: Computed Tomography

CT (Computed Tomography) uses X-ray technology and computer processing to create detailed cross-sectional images of the body.

Question 56: Which statement best describes the principle of informed consent?

Consent is implied once the patient enters the radiology department
The patient must be given a full explanation of the procedure, risks, benefits, and alternatives before voluntarily agreeing (Correct answer)
The patient signs a form without needing a full explanation of the procedure
Consent may be obtained by any staff member regardless of their role

Correct answer: The patient must be given a full explanation of the procedure, risks, benefits, and alternatives before voluntarily agreeing

Informed consent requires full disclosure of the procedure, risks, benefits, and alternatives so the patient can make a voluntary, knowledgeable decision.

Question 57: Which oral contrast agent is most commonly used in CT of the abdomen and pelvis to opacify the bowel?

Air alone as a negative contrast agent
Gadolinium-based oral agent
Barium sulfate suspension or dilute water-soluble iodinated contrast (Correct answer)
Manganese chloride solution

Correct answer: Barium sulfate suspension or dilute water-soluble iodinated contrast

Barium sulfate or dilute iodinated contrast (e.g., dilute Gastrografin) are the standard oral agents used to opacify the GI tract in abdominal/pelvic CT.

Question 58: The ARRT CT post-primary examination is a computer-based test (CBT). Approximately how many scored questions does it contain?

100 questions
200 questions
75 questions
165 questions (Correct answer)

Correct answer: 165 questions

The ARRT CT examination consists of approximately 165 scored questions plus a small number of unscored pilot questions.

Question 59: Increasing the reconstruction field of view (FOV) while keeping matrix size constant will:

Decrease pixel size and increase spatial resolution
Have no effect on spatial resolution
Increase pixel size and decrease spatial resolution (Correct answer)
Increase noise while improving contrast

Correct answer: Increase pixel size and decrease spatial resolution

Larger FOV with the same matrix means each pixel covers more area, increasing pixel size and reducing spatial resolution.

Question 60: On axial CT, the cisterna chyli is typically located at which vertebral level and position?

Posterior to the aorta at T4-T5
Within the retrocrural space at T12-L1
Anterior to L2-L3 between the aorta and IVC (Correct answer)
Lateral to the right crus of the diaphragm at L1-L2

Correct answer: Anterior to L2-L3 between the aorta and IVC

The cisterna chyli is a lymphatic sac located anterior to the L1-L2 vertebral bodies, between the abdominal aorta and the inferior vena cava.

Question 61: Which position is recommended for a patient who is experiencing nausea and vomiting while supine on the radiographic table?

Trendelenburg position
Place the patient prone immediately
Turn the patient's head to the side and lower the table to a semi-recumbent position (Correct answer)
Elevate both legs above heart level

Correct answer: Turn the patient's head to the side and lower the table to a semi-recumbent position

Turning the head to the side prevents aspiration, and lowering the table helps prevent further nausea triggered by the supine position.

Question 62: Which document must a CT examination candidate submit to verify completion of required clinical experience?

A personal statement of clinical hours
Attestation signed by the supervising radiologist or program director (Correct answer)
An IRS tax form showing employment
A letter from the hospital CEO

Correct answer: Attestation signed by the supervising radiologist or program director

ARRT requires an attestation from a qualified supervisor verifying that the candidate met clinical competency requirements.

Question 63: CT calcium scoring of the coronary arteries uses which post-processing method to quantify calcification?

MIP projection over the cardiac cycle
Volume rendering with opacity mapping
Subtraction of non-contrast from contrast images
Agatston scoring based on lesion area and peak Hounsfield unit density (Correct answer)

Correct answer: Agatston scoring based on lesion area and peak Hounsfield unit density

Agatston scoring multiplies the area of each calcified lesion by a density factor based on peak HU (1–4 scale), then sums all lesions to yield the total calcium score.

Question 64: What is HIPAA?

Health Insurance Portability and Accountability Act — protects patient privacy (Correct answer)
A hospital ranking system
A type of insurance plan
A medical diagnosis code

Correct answer: Health Insurance Portability and Accountability Act — protects patient privacy

HIPAA establishes national standards for protecting patient health information, ensuring privacy and security of medical records.

Question 65: In CT, iterative reconstruction (IR) algorithms primarily allow dose reduction by:

Eliminating beam hardening artifacts entirely
Increasing spatial resolution without any dose penalty
Producing diagnostic-quality images at lower mAs settings than filtered back projection (Correct answer)
Reducing the number of detector rows required

Correct answer: Producing diagnostic-quality images at lower mAs settings than filtered back projection

Iterative reconstruction models image noise mathematically, allowing lower mAs protocols to produce acceptable image quality compared to filtered back projection.

Question 66: A horizontal band of decreased attenuation passing through the posterior fossa on a head CT is a classic example of which artifact?

Motion artifact from cardiac pulsation
Partial volume artifact
Ring artifact
Beam hardening between the petrous bones (Correct answer)

Correct answer: Beam hardening between the petrous bones

The dense petrous temporal bones cause preferential absorption of lower-energy photons, producing a dark band across the posterior fossa known as a beam hardening artifact.

Question 67: Which factor does NOT directly influence the CTDI_vol value displayed on the CT console?

Pitch
kVp
Tube current (mAs)
Reconstruction kernel (filter) (Correct answer)

Correct answer: Reconstruction kernel (filter)

Reconstruction kernel is a post-processing parameter applied after data acquisition and does not change the radiation output; CTDI_vol reflects acquisition parameters only.

Question 68: Which CT parameter most directly controls the amount of radiation dose delivered to the patient?

mAs (Correct answer)
Reconstruction kernel
kVp
Pitch

Correct answer: mAs

mAs (milliampere-seconds) directly determines the number of X-ray photons produced and is the primary controller of patient dose.

Question 69: How often must an ARRT CT certification be renewed?

Every 2 years (Correct answer)
Every 3 years
Every 10 years
Every 5 years

Correct answer: Every 2 years

ARRT CT certification, like most ARRT credentials, requires regular renewal to ensure technologists maintain current knowledge and skills. Certified professionals must renew their certification every two years. This biennial renewal process typically involves meeting continuing education requirements.

Question 70: CT colonoscopy (virtual colonoscopy) relies on which post-processing technique to create a simulated fly-through view of the colon lumen?

Volume rendering with endoluminal navigation (Correct answer)
Maximum intensity projection
Subtraction imaging
Minimum intensity projection

Correct answer: Volume rendering with endoluminal navigation

Volume rendering with endoluminal navigation uses the air-distended colon as a flight path, generating a simulated colonoscopic perspective of the mucosal surface.

Question 71: The 'noise power spectrum' (NPS) in CT characterizes noise by:

Measuring total noise as a single RMS value
Counting the number of noisy pixels per slice
Describing how noise energy is distributed across spatial frequencies (Correct answer)
Comparing noise before and after contrast injection

Correct answer: Describing how noise energy is distributed across spatial frequencies

The NPS (or Wiener spectrum) describes the frequency distribution of noise variance, distinguishing coarse (low-frequency) from fine (high-frequency) noise textures.

Question 72: How often must ARRT CT technologists renew their registration?

Every 5 years
Every 2 years (Correct answer)
Annually
Every 3 years

Correct answer: Every 2 years

ARRT registration is renewed on a biennial (every 2 years) basis, coinciding with the CE credit cycle.

Question 73: Which factor primarily determines the z-axis (longitudinal) resolution in a multislice CT scanner?

Gantry rotation speed
Detector row width (Correct answer)
Reconstruction matrix size
kVp setting

Correct answer: Detector row width

Z-axis resolution is primarily determined by detector row width (collimation), which defines slice thickness in the longitudinal direction.

Question 74: A CT technologist holds both Radiography (R) and CT credentials. How many CE credits are required biennially?

12 per credential for a total of 24
24 total, shared across all credentials (Correct answer)
48 total (24 per credential)
24 R-specific + 12 CT-specific = 36

Correct answer: 24 total, shared across all credentials

ARRT allows CE credits to be shared across all held credentials, so 24 credits per 2-year cycle satisfies requirements for multiple credentials.

Question 75: A patient with a cardiac pacemaker presents for chest CT. Which artifact should the technologist anticipate?

Metallic streak artifact from the pacemaker leads and generator (Correct answer)
Cupping artifact
Ring artifact
Windmill artifact

Correct answer: Metallic streak artifact from the pacemaker leads and generator

Pacemaker generators and leads are highly attenuating metallic objects that produce characteristic beam hardening streak artifacts on chest CT.

Question 76: Within what timeframe must newly certified CT technologists complete their first renewal cycle?

Two years from certification date
When their primary registration expires (Correct answer)
One year from certification date
Three years from certification date

Correct answer: When their primary registration expires

Post-primary certification renewal is typically aligned with the technologist's primary registration renewal date, not a separate independent cycle.

Question 77: During a CT-guided biopsy procedure, which measure BEST reduces radiation exposure to the interventional CT technologist?

Standing at the gantry opening throughout the procedure
Wearing a lead apron only when the patient is being positioned
Reducing tube current to zero between acquisitions
Using fluoroscopy-like CT intermittently and stepping back during exposures (Correct answer)

Correct answer: Using fluoroscopy-like CT intermittently and stepping back during exposures

Intermittent CT fluoroscopy combined with stepping away from the gantry during exposures significantly reduces occupational dose during interventional procedures.

Question 78: The spatial resolution of a CT image is primarily limited by which factor?

Focal spot size and detector aperture (Correct answer)
Patient age
Type of reconstruction filter used alone
Room temperature

Correct answer: Focal spot size and detector aperture

Focal spot size and detector cell aperture are the primary hardware factors limiting spatial resolution in CT.

Question 79: Which artifact appears as a dark band between two high-density objects on a CT image and is caused by beam hardening?

Moiré artifact
Windmill artifact
Ring artifact
Shadowing or 'dark band' artifact (Correct answer)

Correct answer: Shadowing or 'dark band' artifact

Dark bands (also called 'shadowing' or 'cupping' between dense objects) arise from extreme beam hardening where few low-energy photons survive to reach the detector between two dense structures.

Question 80: Minimum intensity projection (MinIP) post-processing is particularly useful for displaying which anatomical structures?

Contrast-enhanced blood vessels
Air-filled airways and lung parenchyma (Correct answer)
Solid abdominal organs
Dense bone and calcifications

Correct answer: Air-filled airways and lung parenchyma

MinIP projects the lowest attenuation voxel along each ray, making it ideal for displaying air-containing structures like the tracheobronchial tree or emphysematous lung.

Question 81: Which category of ARRT continuing education credit requires direct patient care activities or case-based learning?

Category B
Category C
Category A (Correct answer)
Category D

Correct answer: Category A

ARRT Category A credits are structured learning activities, often directly tied to clinical or patient-care-relevant content.

Question 82: How often must ARRT-certified technologists complete continuing education to maintain their credentials?

Every 3 years
Every year
Every 5 years
Every 2 years (Correct answer)

Correct answer: Every 2 years

ARRT requires 24 continuing education credits every 2 years to maintain certification.

Question 83: Which window setting is most appropriate for evaluating pulmonary nodules in the lung parenchyma?

Window width ~3000 HU, window level ~300 HU
Window width ~200 HU, window level ~80 HU
Window width ~1500 HU, window level ~-600 HU (Correct answer)
Window width ~400 HU, window level ~40 HU

Correct answer: Window width ~1500 HU, window level ~-600 HU

Lung windows use a wide width (~1500 HU) and negative level (~-600 HU) to display the full range of lung attenuation from air to soft tissue.

Question 84: Which statement about the ARRT CT examination content specifications is accurate?

They mirror the ACR practice parameters exactly
They are developed and periodically updated by ARRT based on practice analysis surveys (Correct answer)
They have not changed since 2000
They are set by individual state radiation control programs

Correct answer: They are developed and periodically updated by ARRT based on practice analysis surveys

ARRT periodically conducts practice analysis surveys of working technologists to keep examination content relevant to current clinical practice.

Question 85: Extravasation of iodinated contrast media into surrounding tissue most commonly occurs due to:

Allergic reaction to the contrast agent
Patient movement during injection
Contrast being injected too slowly
Needle or catheter dislodgement from the vein during power injection (Correct answer)

Correct answer: Needle or catheter dislodgement from the vein during power injection

Extravasation typically results from needle or catheter displacement from the vessel lumen, allowing contrast to leak into the interstitial tissue.

Question 86: Which window setting is most appropriate for evaluating acute intracranial hemorrhage on a non-contrast head CT?

Brain window (WW 80, WL 35) (Correct answer)
Soft tissue window (WW 400, WL 50)
Bone window (WW 2000, WL 300)
Lung window (WW 1500, WL -500)

Correct answer: Brain window (WW 80, WL 35)

The brain window (narrow width ~80 HU, level ~35 HU) provides optimal contrast between hyperdense blood and surrounding brain tissue.

Question 87: What is a key requirement related to clinical experience for ARRT CT certification eligibility?

Document and complete a set of clinical competencies in CT imaging (Correct answer)
Attend a CT-specific conference or seminar
Work in a CT department for a minimum of one year
Perform at least 10 supervised CT scans

Correct answer: Document and complete a set of clinical competencies in CT imaging

A crucial requirement for ARRT CT certification is demonstrating practical proficiency through documented clinical experience. Candidates must complete a specified set of clinical competencies, which involve performing and documenting various CT procedures under supervision. This ensures they have hands-on experience and can safely and effectively operate CT equipment.

Question 88: Which pancreatic landmark on CT imaging marks the junction between the head and body of the pancreas?

The splenic artery origin from the celiac axis
The main pancreatic duct (duct of Wirsung)
The superior mesenteric vein crossing the pancreas (Correct answer)
The common bile duct entering the pancreatic head

Correct answer: The superior mesenteric vein crossing the pancreas

The superior mesenteric vein crosses the anterior surface of the pancreas at the junction of the head and body.

Question 89: Which statement best describes an isotropic voxel in CT imaging?

A voxel that contains only one tissue type
A voxel with maximum attenuation value
A voxel reconstructed using iterative algorithms
A voxel with equal dimensions in x, y, and z axes (Correct answer)

Correct answer: A voxel with equal dimensions in x, y, and z axes

Isotropic voxels have equal measurements in all three spatial dimensions, enabling high-quality MPR and 3D reconstructions in any plane without stair-step degradation.

Question 90: Which reconstruction kernel (filter) choice produces the HIGHEST spatial resolution but MOST noise in CT?

Soft/smooth kernel
Lung kernel
Sharp/edge-enhancing kernel (Correct answer)
Standard kernel

Correct answer: Sharp/edge-enhancing kernel

Sharp or bone kernels enhance high-frequency data to improve edge detail but amplify noise, making them high-resolution but noisy.

Question 91: A 'blooming artifact' in CT most commonly results from:

High-density metallic objects causing overestimation of structure size (Correct answer)
Incorrect HU calibration of the scanner
Undersampling of high-frequency data
Patient motion during acquisition

Correct answer: High-density metallic objects causing overestimation of structure size

Blooming occurs when high-attenuation objects like metals or calcifications appear larger than their true size due to beam hardening and partial volume effects.

Question 92: A CT technologist is audited by ARRT and cannot produce records for completed CE activities. What is the most likely consequence?

A formal written warning is issued
They are required to repeat the certification exam
Their CE credits may be disallowed and registration revoked (Correct answer)
ARRT will contact the CE sponsors on their behalf

Correct answer: Their CE credits may be disallowed and registration revoked

During an audit, failure to document CE activities can result in disallowance of credits and potential revocation of registration.

Question 93: A patient asks the radiologic technologist about the radiation dose they will receive from a CT scan. The best response is to:

Dismiss the concern since modern CT scanners are considered completely safe
Explain that CT doses are too complex to explain to patients
Tell the patient the dose information is confidential
Provide a general explanation of the dose and the benefit-risk balance while referring detailed questions to the radiologist (Correct answer)

Correct answer: Provide a general explanation of the dose and the benefit-risk balance while referring detailed questions to the radiologist

Patients have the right to understand their radiation exposure; the technologist should provide a clear, honest explanation and involve the radiologist for detailed clinical questions.

Question 94: On axial CT of the neck, the hypopharynx is best visualized at which vertebral level?

C3-C4
C4-C6 (Correct answer)
C7-T1
C1-C2

Correct answer: C4-C6

The hypopharynx extends from the level of the hyoid bone (C3) to the cricopharyngeus muscle (C6), and is best visualized on CT at C4-C6.

Question 95: Which body administers the ARRT CT certification examination at testing centers?

ACR regional offices
JRCERT-affiliated schools
ARRT staff at ARRT headquarters
Prometric (Correct answer)

Correct answer: Prometric

ARRT partners with Prometric to deliver its certification examinations at testing centers nationwide.

Question 96: What is the primary advantage of CT over conventional X-ray?

CT takes less time
CT is cheaper
CT uses no radiation
CT provides cross-sectional images with superior soft tissue contrast (Correct answer)

Correct answer: CT provides cross-sectional images with superior soft tissue contrast

CT provides detailed cross-sectional images with much better soft tissue contrast resolution than conventional X-rays, allowing visualization of subtle differences between tissues.

Question 97: What is the window level and window width on CT images?

Settings that control the brightness and contrast of displayed images (Correct answer)
Scan speed controls
Patient positioning parameters
Physical measurements of the CT scanner

Correct answer: Settings that control the brightness and contrast of displayed images

Window level sets the center brightness (what HU appears as middle gray) and window width controls contrast range (how many HUs span from black to white).

Question 98: What is the minimum passing score for the ARRT CT certification exam?

70
65
75 (Correct answer)
80

Correct answer: 75

To successfully pass the ARRT CT certification exam, candidates must achieve a scaled score of 75 or higher. This score represents the minimum level of competency required by the ARRT to demonstrate proficiency in computed tomography. Scores are scaled to ensure fairness across different exam forms.

Question 99: Which statement BEST describes the relationship between CT noise and mAs?

Noise is inversely proportional to mAs
Noise is unaffected by mAs changes
Noise is directly proportional to mAs
Noise is proportional to 1/√mAs (Correct answer)

Correct answer: Noise is proportional to 1/√mAs

CT noise follows Poisson statistics; doubling mAs quadruples photons but only reduces noise by a factor of √2, making noise proportional to 1/√mAs.

Question 100: A newly certified CT technologist wants to transition from a general hospital to an outpatient imaging center. How does ARRT CT certification help?

It automatically transfers the technologist's state license to the new facility
It eliminates the need for any additional facility orientation
It demonstrates specialized competency that outpatient centers increasingly require for hiring (Correct answer)
It restricts employment to inpatient facilities only

Correct answer: It demonstrates specialized competency that outpatient centers increasingly require for hiring

Outpatient imaging centers often prefer or require ARRT CT certification as proof of specialized competency, making job transitions easier.

Question 101: Which radiation weighting factor (wR) applies to X-rays used in CT imaging?

5
2
1 (Correct answer)
20

Correct answer: 1

X-rays and gamma rays have a radiation weighting factor of 1, meaning 1 Gy equals 1 Sv.

Question 102: The window level (WL) in CT display refers to:

The center Hounsfield unit value of the displayed grayscale range (Correct answer)
The total range of Hounsfield units shown
The reconstruction matrix size
The minimum threshold for bone segmentation

Correct answer: The center Hounsfield unit value of the displayed grayscale range

Window level sets the midpoint of the HU range being displayed, determining which tissue densities appear as medium gray on the monitor.

Question 103: What are the principles of mission command?

Speed, power, aggression
Technology, firepower, logistics
Competence, mutual trust, shared understanding, commander's intent (Correct answer)
Rank, authority, obedience

Correct answer: Competence, mutual trust, shared understanding, commander's intent

Mission command empowers subordinates through trust, shared understanding of the commander's intent, and disciplined initiative.

Question 104: What happens if an ARRT CT-certified technologist fails to meet the recertification requirements?

They must apply for a temporary certification until they meet the requirements
Their certification status becomes inactive, and they cannot work as a CT technologist (Correct answer)
They receive a grace period to meet the requirements without penalty
Their certification is automatically revoked, and they must retake the certification exam

Correct answer: Their certification status becomes inactive, and they cannot work as a CT technologist

Failure to meet ARRT CT recertification requirements, such as completing the necessary continuing education, results in the certification becoming inactive. An inactive certification means the individual is no longer recognized as an ARRT-certified CT technologist and cannot legally or professionally practice under that credential.

Question 105: On a CT scanner, what does image uniformity testing evaluate?

The linearity of dose output versus mAs
The accuracy of the patient table indexing
The ability to visualize small high-contrast structures
The consistency of CT numbers across the field of view in a homogeneous phantom (Correct answer)

Correct answer: The consistency of CT numbers across the field of view in a homogeneous phantom

Image uniformity testing measures whether a homogeneous phantom (e.g., water) produces consistent HU values across the entire reconstructed image.

Question 106: What is the primary purpose of selecting a small reconstruction FOV (field of view) during CT image reconstruction?

To reduce patient dose
To increase the pixel size for better soft tissue contrast
To improve spatial resolution by sampling more detail per pixel (Correct answer)
To decrease image noise

Correct answer: To improve spatial resolution by sampling more detail per pixel

A smaller reconstruction FOV divides the imaged area into the same matrix of pixels, resulting in smaller pixel size and therefore higher spatial resolution of the region of interest.

Question 107: CT window width (WW) setting controls which aspect of image display?

The range of Hounsfield units displayed as the full gray scale from black to white (Correct answer)
The overall brightness of the image
The center Hounsfield unit of the gray scale
The spatial resolution of the image

Correct answer: The range of Hounsfield units displayed as the full gray scale from black to white

Window width determines the range of CT numbers (HU) mapped to the grayscale; a narrow window increases contrast but limits the HU range displayed.

Question 108: How many continuing education (CE) credits must ARRT-certified technologists earn in each biennium to maintain eligibility for CT certification renewal?

12 credits
48 credits
24 credits (Correct answer)
36 credits

Correct answer: 24 credits

ARRT requires 24 CE credits per two-year renewal cycle to maintain an active, unrestricted credential.

Question 109: A CT abdomen reveals a liver lesion that is hypodense on non-contrast, enhances intensely on arterial phase, and becomes isodense to liver on portal venous phase. This pattern is most consistent with:

Hepatocellular carcinoma (Correct answer)
Cholangiocarcinoma
Focal nodular hyperplasia
Hepatic hemangioma

Correct answer: Hepatocellular carcinoma

Arterial hyperenhancement with washout on portal venous phase is the classic CT hallmark of hepatocellular carcinoma.

Question 110: Which scan parameter adjustment would best reduce streak artifact from dental fillings on a head/neck CT?

Use gantry tilt to avoid the plane of the fillings (Correct answer)
Decrease tube voltage
Decrease rotation time
Increase tube current (mA)

Correct answer: Use gantry tilt to avoid the plane of the fillings

Tilting the gantry angles the scan plane away from dense dental hardware, reducing the metal streak artifact through structures of interest.

Question 111: For a trauma CT protocol of the chest, which contrast phase is typically acquired?

Non-contrast only
Delayed phase only
Arterial phase only
Portal venous phase (Correct answer)

Correct answer: Portal venous phase

The portal venous phase (~60–70 seconds post-injection) provides optimal parenchymal enhancement to detect solid organ injuries in chest trauma.

Question 112: The right coronary artery is most reliably identified on axial CT in which anatomical groove?

Posterior interventricular groove
Left atrioventricular groove
Right atrioventricular (coronary) groove (Correct answer)
Anterior interventricular groove

Correct answer: Right atrioventricular (coronary) groove

The right coronary artery runs within the right atrioventricular groove between the right atrium and right ventricle.

Question 113: On axial CT of the chest, the right and left main bronchi are best distinguished because:

The right main bronchus is longer and more horizontal than the left
The left main bronchus has a larger caliber than the right
The right main bronchus is shorter and more vertical, making aspiration more likely (Correct answer)
The left main bronchus is shorter and more vertical than the right

Correct answer: The right main bronchus is shorter and more vertical, making aspiration more likely

The right main bronchus is shorter, wider, and more vertical, which is why aspirated foreign bodies most commonly lodge on the right side.

Question 114: Which CT post-processing technique displays only voxels above a selected threshold, making it useful for 3D visualization of bones and vascular structures?

Volume rendering (VR)
Maximum intensity projection (MIP) (Correct answer)
Multiplanar reformation (MPR)
Surface shaded display (SSD)

Correct answer: Maximum intensity projection (MIP)

Maximum intensity projection (MIP) selects and displays the highest attenuation voxel along each ray through the dataset, ideal for visualizing contrast-enhanced vessels or calcifications.

Question 115: What is a Hounsfield unit?

A quantitative measurement of tissue density on CT images (Correct answer)
A unit of radiation dose
A measure of scan speed
A unit of image resolution

Correct answer: A quantitative measurement of tissue density on CT images

Hounsfield units (HU) measure tissue density on CT, with water at 0 HU, air at -1000 HU, and dense bone at +1000 HU or higher.

Question 116: A pregnant patient requires urgent abdominal CT. What is the approximate threshold fetal dose below which deterministic effects (e.g., malformations) are considered negligible?

100 mGy
50 mGy (Correct answer)
500 mGy
5 mGy

Correct answer: 50 mGy

Below approximately 50 mGy, deterministic effects such as malformations or growth retardation are not expected; however, stochastic risk remains and dose should be minimized.

Question 117: How many questions are typically included in the ARRT CT certification exam?

150 (Correct answer)
200
100
250

Correct answer: 150

The ARRT CT certification exam typically consists of 150 questions. This number includes both scored and unscored pilot questions, designed to comprehensively assess a candidate's knowledge across various domains of computed tomography. Candidates are given a specific time limit to complete all questions.

Question 118: Which of the following describes the location of the zona incerta on axial CT brain images?

Gray matter located in the posterior limb of the internal capsule
A thin band of gray matter between the lenticular fasciculus and the thalamic fasciculus in the subthalamus (Correct answer)
A sulcus separating the caudate from the putamen
A white matter tract connecting the thalamus to the frontal lobe

Correct answer: A thin band of gray matter between the lenticular fasciculus and the thalamic fasciculus in the subthalamus

The zona incerta is a subthalamic gray matter band situated between the lenticular and thalamic fasciculi.

Question 119: Which patient factor most directly increases the risk of contrast extravasation injury severity?

Use of nonionic rather than ionic contrast
Prior allergic contrast reaction
Large volume of high-concentration contrast extravasated under high pressure (Correct answer)
Patient age under 30 years

Correct answer: Large volume of high-concentration contrast extravasated under high pressure

Large volumes of high-concentration contrast extravasated at high pressure cause greater tissue injury due to osmotic and volume effects on surrounding soft tissue.

Question 120: What is the primary purpose of ARRT's structured competency-based renewal requirements for CT certification?

To increase revenue for the ARRT organization
To limit the number of active CT technologists
To ensure technologists maintain current knowledge and skills (Correct answer)
To align with Medicare billing requirements

Correct answer: To ensure technologists maintain current knowledge and skills

ARRT's renewal structure is designed to ensure that certified professionals stay current with evolving technology, safety standards, and clinical practice.

Question 121: What is the function of red blood cells?

To fight infection
To clot blood
To transport oxygen from lungs to tissues and CO2 back (Correct answer)
To produce hormones

Correct answer: To transport oxygen from lungs to tissues and CO2 back

Red blood cells (erythrocytes) contain hemoglobin that binds oxygen in the lungs and delivers it to tissues, then carries carbon dioxide back for exhalation.

Question 122: What is the function of red blood cells?

To produce hormones
To clot blood
To transport oxygen from lungs to tissues and CO2 back (Correct answer)
To fight infection

Correct answer: To transport oxygen from lungs to tissues and CO2 back

Red blood cells (erythrocytes) contain hemoglobin that binds oxygen in the lungs and delivers it to tissues, then carries carbon dioxide back for exhalation.

Question 123: The ARRT CT post-primary examination content specifications are reviewed and updated approximately every:

1 year
5 years (Correct answer)
Every certification cycle (2 years)
10 years

Correct answer: 5 years

ARRT reviews and updates examination content specifications on approximately a five-year cycle through its practice analysis process.

Question 124: Which measurement best quantifies the amount of iodine delivered to a patient per unit time during a CT angiography injection?

Injection pressure in PSI
Iodine delivery rate (IDR) expressed as grams of iodine per second (Correct answer)
Total contrast volume in mL
Iodine concentration in mg/mL alone

Correct answer: Iodine delivery rate (IDR) expressed as grams of iodine per second

Iodine delivery rate (IDR = concentration [mgI/mL] × flow rate [mL/s]) determines the rate of iodine reaching the vascular system and predicts enhancement quality better than volume alone.

Question 125: A patient undergoing a radiographic exam becomes unresponsive and pulseless. The technologist should FIRST:

Place the patient in recovery position and observe
Administer oxygen via nasal cannula
Begin chest compressions immediately while calling for help (Correct answer)
Activate the emergency response system (call code)

Correct answer: Begin chest compressions immediately while calling for help

According to current AHA guidelines, high-quality chest compressions should begin immediately while simultaneously calling for emergency help.

Question 126: A CT enterography protocol differs from a standard abdominal CT primarily in which way?

Use of oral contrast to distend the small bowel (Correct answer)
Scanning only the large intestine
Higher tube current for better resolution
Intravenous contrast is not used

Correct answer: Use of oral contrast to distend the small bowel

CT enterography uses large volumes of neutral oral contrast (e.g., VoLumen) to distend and visualize the small bowel mucosa.

Question 127: How does ARRT CT certification support a technologist's participation in quality improvement initiatives within their department?

It transfers QI responsibilities entirely to the radiologist
It disqualifies technologists from serving on quality committees
It provides the advanced protocol and dose optimization knowledge needed to contribute meaningfully to QI projects (Correct answer)
It only applies to patient scheduling improvements

Correct answer: It provides the advanced protocol and dose optimization knowledge needed to contribute meaningfully to QI projects

The depth of CT knowledge required for ARRT certification equips technologists to identify protocol inefficiencies, dose issues, and image quality problems in QI settings.

Question 128: An imaging manager reviewing candidates for a CT position ranks an ARRT(CT)-certified applicant higher than an uncertified one. Which professional benefit does this reflect?

Competitive advantage in the job market due to validated specialty competency (Correct answer)
Guaranteed productivity metrics from certified staff
Reduced need for the certified technologist to attend department meetings
Lower salary demands from certified candidates

Correct answer: Competitive advantage in the job market due to validated specialty competency

ARRT CT certification provides a competitive edge during hiring by assuring employers of validated, standardized CT competency without requiring internal testing.

Question 129: What is the application window for the ARRT CT post-primary examination after a candidate is deemed eligible?

Six months from approval to test
One year from approval to test (Correct answer)
Two years from approval to test
30 days from approval to test

Correct answer: One year from approval to test

Once approved, ARRT candidates have one year to schedule and sit for the post-primary CT examination.

Question 130: In CT, the filtered back projection (FBP) reconstruction algorithm applies a mathematical filter primarily to:

Align misregistered projection data
Segment soft tissue from bone
Correct for star artifacts inherent in simple back projection (Correct answer)
Remove quantum noise before reconstruction

Correct answer: Correct for star artifacts inherent in simple back projection

FBP applies a ramp or other convolution filter to projection data before back-projecting to eliminate the blurring ('star artifact') produced by simple back projection.

Question 131: When performing a venipuncture for contrast administration, the needle bevel should be oriented:

At a 90-degree angle to the skin
Facing up (bevel up) (Correct answer)
Facing down toward the vein wall
Parallel to the skin surface, bevel sideways

Correct answer: Facing up (bevel up)

The bevel-up orientation allows the needle to enter the vein smoothly and reduces the risk of piercing the posterior vein wall.

Question 132: A CT of the chest shows a 2.5 cm solitary pulmonary nodule with central 'popcorn' calcification. What is the most likely diagnosis?

Bronchogenic carcinoma
Carcinoid tumor
Metastatic deposit
Hamartoma (Correct answer)

Correct answer: Hamartoma

Popcorn calcification within a pulmonary nodule is characteristic of a pulmonary hamartoma.

Question 133: Which of the following best describes the purpose of a test bolus or bolus tracking technique in CT angiography?

To eliminate venous contamination
To improve bone subtraction
To reduce overall contrast volume needed
To determine the optimal scan delay for peak arterial enhancement (Correct answer)

Correct answer: To determine the optimal scan delay for peak arterial enhancement

Test bolus or bolus-tracking (SmartPrep/SureStar) determines when contrast peaks in the target vessel so scanning begins at the optimal moment.

Question 134: On axial CT of the knee, the iliotibial band is best identified at which location?

Anteromedial compartment between the patellar tendon and medial collateral ligament
Posterolateral aspect of the knee, inserting on the femoral condyle
Posterior to the lateral collateral ligament at the fibular head
Lateral aspect of the knee, inserting on Gerdy's tubercle of the tibia (Correct answer)

Correct answer: Lateral aspect of the knee, inserting on Gerdy's tubercle of the tibia

The iliotibial band runs along the lateral thigh and inserts on Gerdy's tubercle on the anterolateral tibia.

Question 135: On CT angiography of the aorta, which finding is pathognomonic of an aortic dissection?

Periaortic hematoma
Mural thrombus
An intimal flap separating true and false lumens (Correct answer)
Aortic dilation greater than 5 cm

Correct answer: An intimal flap separating true and false lumens

An intimal flap creating two distinct lumens (true and false) is the defining CT finding of aortic dissection.

Question 136: What is one key reason that ACR-accredited imaging facilities value technologists with ARRT CT certification?

ACR accreditation prohibits hiring uncertified technologists
Certified technologists help demonstrate staff qualifications required during ACR accreditation reviews (Correct answer)
Accreditation requires a minimum ratio of 10 certified techs per scanner
ARRT CT certification is issued by the ACR

Correct answer: Certified technologists help demonstrate staff qualifications required during ACR accreditation reviews

ACR accreditation reviewers assess staff qualifications, and ARRT CT certification is recognized evidence of competency that supports accreditation approval.

Question 137: On axial CT of the pelvis in a female patient, the uterus is characteristically located:

Posterior to the urinary bladder and anterior to the rectum (Correct answer)
Anterior to the urinary bladder in the retropubic space
Lateral to the cervix between the external iliac vessels
Posterior to the rectum at the level of the sacrum

Correct answer: Posterior to the urinary bladder and anterior to the rectum

The uterus lies between the urinary bladder anteriorly and the rectum posteriorly in the true pelvis.

Question 138: In CT, the term 'pitch' for single-slice CT is calculated as:

Table speed / gantry rotation time
kVp / mAs
Table feed per rotation / slice thickness (Correct answer)
Detector width / field of view

Correct answer: Table feed per rotation / slice thickness

Pitch = table feed per 360° rotation divided by the nominal slice thickness; a pitch >1 means gaps exist between consecutive slices.

Question 139: Which artifact is caused by patient movement during CT data acquisition and appears as blurring or ghosting on the reconstructed image?

Motion artifact (Correct answer)
Aliasing artifact
Partial volume artifact
Cupping artifact

Correct answer: Motion artifact

Motion artifacts result from patient movement during scanning, causing inconsistent data at each projection angle and manifesting as blurring or streaking.

Question 140: Which of the following best describes the CT appearance of the caudate lobe of the liver?

Located posterior to the inferior vena cava and anterior to the portal vein
A small segment located between the IVC and the fissure for the ligamentum venosum (Correct answer)
The largest segment of the left hepatic lobe
Located between the gallbladder fossa and the fissure for the ligamentum teres

Correct answer: A small segment located between the IVC and the fissure for the ligamentum venosum

The caudate lobe (segment I) lies between the IVC posteriorly and the fissure for the ligamentum venosum anteriorly.

Question 141: A CT technologist with ARRT CT certification wants to teach at a community college radiologic technology program. How does the certification help?

It only qualifies the technologist to teach radiography, not CT specifically
It is a disqualifying credential for educational roles
It demonstrates content expertise that many programs require or prefer for adjunct CT instructors (Correct answer)
It automatically grants a teaching license in all states

Correct answer: It demonstrates content expertise that many programs require or prefer for adjunct CT instructors

Community college and vocational radiologic technology programs often require or prefer instructors to hold advanced ARRT credentials in the specialty they are teaching.

Question 142: Curved planar reformation (CPR) in CT is most useful for:

Generating endoscopic views of hollow organs
Straightening and displaying tortuous structures such as vessels or the spine along their entire length (Correct answer)
Subtracting bone from CT angiography images
Creating color-coded perfusion maps

Correct answer: Straightening and displaying tortuous structures such as vessels or the spine along their entire length

CPR follows a user-defined curved path through the volume dataset to display a tortuous structure in a single unfolded plane, useful for coronary arteries or the aorta.

Question 143: What type of artifact appears as bright or dark streaks radiating from high-density objects like metal implants in CT images?

Ring artifact
Partial volume artifact
Motion artifact
Beam hardening artifact (Correct answer)

Correct answer: Beam hardening artifact

Beam hardening artifacts appear as streaks or dark bands radiating from dense metallic objects because lower-energy photons are preferentially absorbed.

Question 144: On axial CT of the abdomen, the superior mesenteric artery (SMA) is typically located:

Within the hepatoduodenal ligament
Directly anterior to the abdominal aorta, surrounded by fat (Correct answer)
Posterior to the splenic vein
Lateral to the inferior vena cava

Correct answer: Directly anterior to the abdominal aorta, surrounded by fat

The SMA arises from the anterior aorta and is typically seen as a vessel surrounded by a halo of mesenteric fat on axial CT.

Question 145: Which of the following best describes an out-of-field artifact in CT?

Ring caused by detector failure
Streaking caused by anatomy extending beyond the scan FOV (Correct answer)
Blurring from respiratory motion
Noise from low mAs

Correct answer: Streaking caused by anatomy extending beyond the scan FOV

Out-of-field artifacts occur when part of the patient's anatomy lies outside the calibrated scan FOV, causing truncation of projection data and bright peripheral streaks.

Question 146: The 'cupping artifact' in CT, where the center of a uniform object appears less dense than its periphery, is a manifestation of which phenomenon?

Quantum noise
Beam hardening (Correct answer)
Partial volume averaging
Aliasing

Correct answer: Beam hardening

Cupping artifact is a form of beam hardening where the edges of the object appear brighter because the beam hardens less traveling a shorter path length.

Question 147: Which eGFR threshold does the ACR use to define increased risk for contrast-induced acute kidney injury when administering IV iodinated contrast?

eGFR < 30 mL/min/1.73m² (Correct answer)
eGFR < 90 mL/min/1.73m²
eGFR < 60 mL/min/1.73m²
eGFR < 45 mL/min/1.73m²

Correct answer: eGFR < 30 mL/min/1.73m²

The ACR Manual on Contrast Media identifies eGFR < 30 mL/min/1.73m² as the threshold for significantly increased risk of contrast-induced acute kidney injury.

Question 148: A CT pelvis shows a complex ovarian mass with solid components, calcifications, fat density, and hair-like structures. This is most consistent with:

Endometrioma
Mature cystic teratoma (dermoid cyst) (Correct answer)
Mucinous cystadenoma
Serous cystadenocarcinoma

Correct answer: Mature cystic teratoma (dermoid cyst)

Mature cystic teratomas contain fat, calcium, and soft tissue elements (including teeth or hair) from multiple germ cell layers.

Question 149: Which reconstruction kernel (filter) should be chosen to minimize noise when imaging soft tissue structures in the abdomen?

Bone or edge-enhancing kernel
Ultra-high resolution kernel
Lung kernel
Smooth or standard soft tissue kernel (Correct answer)

Correct answer: Smooth or standard soft tissue kernel

Soft tissue kernels apply low-pass filtering that smooths the image and reduces noise, which is appropriate for abdominal soft tissue evaluation.

Question 150: What is the largest organ in the human body?

Skin (Correct answer)
Heart
Liver
Brain

Correct answer: Skin

The skin is the largest organ, covering approximately 20 square feet in adults and weighing about 8 pounds. It serves as the primary barrier against the environment.

Question 151: On a CT KUB (kidneys, ureters, bladder), which stone type appears LEAST dense (lowest Hounsfield units)?

Calcium oxalate monohydrate
Cystine
Uric acid (Correct answer)
Struvite

Correct answer: Uric acid

Uric acid stones are the least dense urinary calculi on CT (100–400 HU), compared to calcium-based stones which exceed 800 HU.

Question 152: What is the ALARA principle in radiation safety?

Always Lock And Restrict Access
Automated Limiting Adjustment for Radiation Applications
All Labs And Rooms Assessed
As Low As Reasonably Achievable — minimize radiation exposure (Correct answer)

Correct answer: As Low As Reasonably Achievable — minimize radiation exposure

ALARA means keeping radiation doses as low as reasonably achievable while still obtaining diagnostic-quality images, balancing benefit against risk.

Question 153: A CT technologist notices the dose reference level (DRL) for a routine chest CT is being routinely exceeded. The BEST first step is to:

Report the finding only to the radiologist and take no further action
Review and optimize the scan protocol to determine if dose can be reduced without compromising diagnostic quality (Correct answer)
Continue scanning since DRLs are not legally binding limits
Immediately halve the mAs for all chest CT exams

Correct answer: Review and optimize the scan protocol to determine if dose can be reduced without compromising diagnostic quality

DRLs serve as benchmarks; exceeding them triggers a protocol review to identify optimization opportunities while preserving diagnostic image quality.

Question 154: What is the most effective way to prevent healthcare-associated infections?

Cleaning the floor
Wearing gloves at all times
Taking antibiotics
Proper hand hygiene (Correct answer)

Correct answer: Proper hand hygiene

Hand hygiene (washing with soap and water or using alcohol-based hand rub) is the single most effective measure for preventing the spread of infections in healthcare settings.

Question 155: How does ARRT define 'structured education' for CT post-primary eligibility?

Any on-the-job training logged by the supervisor
Self-study using any radiology textbook
Formal coursework covering specific CT content areas as defined by ARRT (Correct answer)
Attendance at a single CT conference or symposium

Correct answer: Formal coursework covering specific CT content areas as defined by ARRT

ARRT requires formal coursework in specific CT content areas as part of its structured education requirement for post-primary eligibility.

Question 156: What is the effect of decreasing detector collimation (thinner slices) on image noise, assuming all other factors remain constant?

Noise is eliminated
Noise is unaffected
Noise decreases
Noise increases (Correct answer)

Correct answer: Noise increases

Thinner collimation means fewer photons contribute to each voxel, increasing statistical noise in the image.

Question 157: Which phenomenon explains why CT numbers for bone may appear elevated at the center of a thick bony structure compared to peripheral bone?

Partial volume effect
Ring artifact
Undersampling artifact
Beam hardening cupping artifact (Correct answer)

Correct answer: Beam hardening cupping artifact

Beam hardening causes preferential absorption of lower-energy photons; more hardening occurs centrally, leading to erroneously high CT numbers at bone edges and low values centrally (cupping).

Question 158: Which of the following best describes the purpose of the CT table indexing accuracy test?

To measure the table speed during helical scans
To evaluate gantry isocenter alignment
To confirm the table moves the correct prescribed distance between scan acquisitions (Correct answer)
To verify the table weight tolerance

Correct answer: To confirm the table moves the correct prescribed distance between scan acquisitions

Table indexing accuracy testing ensures the patient couch advances exactly the specified distance, which is critical for accurate slice positioning and volume coverage.

Question 159: A radiologic technologist notices that CT images of the liver appear uniformly noisy despite using standard mAs. The MOST appropriate first corrective action is:

Reduce the reconstruction FOV by 50%
Verify that the correct reconstruction kernel and algorithm are applied (Correct answer)
Double the mAs for the repeat scan immediately
Switch to a narrower window width for display

Correct answer: Verify that the correct reconstruction kernel and algorithm are applied

Verifying protocol settings (kernel, algorithm, slice thickness) first ensures the source of apparent noise is identified before unnecessarily increasing dose.

Question 160: What is the significance of ARRT accreditation reciprocity with respect to international technologists seeking U.S. credentials?

ARRT does not grant reciprocity; international candidates must meet all ARRT eligibility requirements independently (Correct answer)
ARRT has formal reciprocity agreements with all countries
Foreign technologists are exempt from the ethics review
Foreign credentials are automatically accepted as equivalent to ARRT certification

Correct answer: ARRT does not grant reciprocity; international candidates must meet all ARRT eligibility requirements independently

ARRT does not have reciprocity agreements with foreign credentialing bodies; all candidates must independently meet ARRT's eligibility and examination requirements.

Question 161: Respiratory motion artifacts on chest CT can best be minimized by:

Increasing kVp
Using breath-hold technique during acquisition (Correct answer)
Increasing slice thickness
Widening the display window

Correct answer: Using breath-hold technique during acquisition

Instructing the patient to suspend respiration during CT acquisition eliminates breathing motion, preventing blurring and step artifacts in the chest.

Question 162: Quantum mottle in CT images is primarily caused by:

Detector calibration errors
High kVp beam hardening
An insufficient number of detected photons (Correct answer)
Excessive table speed

Correct answer: An insufficient number of detected photons

Quantum mottle (noise) occurs when too few photons reach the detector, causing statistical fluctuations that appear as grainy image texture.

Question 163: What is the primary advantage of CT over conventional X-ray?

CT provides cross-sectional images with superior soft tissue contrast (Correct answer)
CT is cheaper
CT takes less time
CT uses no radiation

Correct answer: CT provides cross-sectional images with superior soft tissue contrast

CT provides detailed cross-sectional images with much better soft tissue contrast resolution than conventional X-rays, allowing visualization of subtle differences between tissues.

Question 164: Which generator component is responsible for converting AC power to the high-voltage DC supply required by the X-ray tube in modern CT systems?

Filament transformer
High-frequency inverter generator (Correct answer)
Autotransformer
Rectifier diode bridge

Correct answer: High-frequency inverter generator

Modern CT systems use high-frequency inverter generators that convert line AC to high-frequency AC, then rectify it to produce a near-constant high-voltage DC supply for the tube.

Question 165: What does informed consent require?

Verbal agreement only
Getting any signature on a form
Family approval only
Explaining the procedure, risks, benefits, and alternatives to the patient (Correct answer)

Correct answer: Explaining the procedure, risks, benefits, and alternatives to the patient

Informed consent requires that patients understand the proposed procedure, its risks and benefits, alternatives, and have the opportunity to ask questions before agreeing.

Question 166: What is the mechanism of an anaphylactoid (allergic-like) reaction to iodinated contrast media?

IgE-mediated mast cell degranulation identical to classic allergy
Non-IgE-mediated direct mast cell and basophil activation independent of prior sensitization (Correct answer)
Complement activation by iodine forming immune complexes
Cytotoxic T-cell destruction of endothelial cells

Correct answer: Non-IgE-mediated direct mast cell and basophil activation independent of prior sensitization

Anaphylactoid reactions to contrast are non-IgE-mediated; contrast directly activates mast cells and basophils, releasing histamine and other mediators without requiring prior sensitization.

Question 167: The Hounsfield unit (HU) value of pure water is:

+100
+1000
0 (Correct answer)
-1000

Correct answer: 0

By definition, pure water is assigned an HU value of 0 on the Hounsfield scale used in CT imaging.

Question 168: How is the ARRT Computed Tomography (CT) certification exam administered?

Through online remote proctoring
In-person at a hospital or clinic
During an in-person workshop or seminar
At a Pearson VUE testing center (Correct answer)

Correct answer: At a Pearson VUE testing center

The ARRT Computed Tomography (CT) certification exam is administered through a professional testing service. Candidates are required to schedule and take their exam at an authorized Pearson VUE testing center. These centers provide a standardized, secure, and proctored environment for examinations.

Question 169: Which financial benefit is most commonly associated with passing the ARRT CT certification exam for staff technologists?

Eligibility for a certification differential or bonus pay (Correct answer)
Permanent exemption from performance reviews
Free continuing education paid by ARRT
Automatic promotion to radiologist

Correct answer: Eligibility for a certification differential or bonus pay

Many hospitals and imaging facilities offer a certification differential—extra hourly pay or a one-time bonus—when staff earn specialty credentials.

Question 170: Under the ARRT ethics requirement, which of the following past offenses is MOST likely to result in denial of CT certification eligibility?

Minor traffic violation
A civil lawsuit unrelated to healthcare
Felony conviction related to the practice of radiologic technology (Correct answer)
Unpaid parking tickets

Correct answer: Felony conviction related to the practice of radiologic technology

Felony convictions, especially those related to healthcare practice, are subject to ARRT ethics review and can result in denial.

Question 171: 3D volume rendering of CT data allows the display of internal structures through which technique?

Subtracting bone from the dataset
Assigning opacity values to voxels based on their Hounsfield units (Correct answer)
Selecting only the highest attenuation voxel per projection ray
Applying a smooth kernel to the raw data

Correct answer: Assigning opacity values to voxels based on their Hounsfield units

Volume rendering assigns transfer functions that map each HU value to a color and opacity, allowing semi-transparent visualization of multiple tissue types simultaneously.

Question 172: Which of the following is the primary reason for using a low-osmolar, non-ionic iodinated contrast agent for intravenous CT contrast?

It provides higher iodine concentration per mL
It significantly reduces the risk of adverse reactions compared to ionic agents (Correct answer)
It requires a lower injection rate
It is less expensive than ionic contrast

Correct answer: It significantly reduces the risk of adverse reactions compared to ionic agents

Non-ionic, low-osmolar contrast agents have a much lower rate of adverse reactions (including severe reactions) compared to older high-osmolar ionic agents.

Question 173: A radiologic technologist holds R.T.(R)(CT) credentials. What do the letters in parentheses each represent?

(R) = primary ARRT registration in Radiography; (CT) = post-primary CT certification (Correct answer)
(R) = residency completed; (CT) = computed tomography board
(R) = Radiology degree; (CT) = computed tomography license
(R) = state registration; (CT) = federal CT permit

Correct answer: (R) = primary ARRT registration in Radiography; (CT) = post-primary CT certification

R.T.(R) denotes primary ARRT registration in Radiography, and (CT) denotes the additional post-primary CT certification earned.

Question 174: What is the main clinical use of dual-energy CT (DECT)?

Reducing scan time by half
Material decomposition to differentiate tissue composition (e.g., iodine vs. calcium) (Correct answer)
Increasing patient dose efficiency
Eliminating the need for contrast agents entirely

Correct answer: Material decomposition to differentiate tissue composition (e.g., iodine vs. calcium)

DECT acquires data at two different kVp levels; the difference in attenuation at each energy allows material decomposition to characterize tissue composition.

Question 175: Which of the following is a valid reason ARRT may revoke or suspend a technologist's CT certification?

Failure to update a home address in the ARRT database
Violation of the ARRT Standards of Ethics (Correct answer)
Completing CE credits after the renewal deadline
Transferring employment to a different imaging facility

Correct answer: Violation of the ARRT Standards of Ethics

ARRT can revoke or suspend certification for violations of its Standards of Ethics, which govern professional and personal conduct.

Question 176: The inverse square law states that radiation intensity is related to distance by which relationship?

Intensity decreases linearly with distance
Intensity is inversely proportional to the cube of the distance
Intensity is inversely proportional to the square of the distance (Correct answer)
Intensity is directly proportional to distance

Correct answer: Intensity is inversely proportional to the square of the distance

The inverse square law: I ∝ 1/d², meaning doubling the distance from the source reduces intensity to one-quarter of its original value.

Question 177: In CT, the term 'isotropic voxel' means:

The voxel represents a single tissue type
The voxel dimensions are equal in all three axes (x, y, z) (Correct answer)
The voxel has no noise contribution
The voxel's HU value is calibrated to water

Correct answer: The voxel dimensions are equal in all three axes (x, y, z)

An isotropic voxel has equal dimensions in x, y, and z directions, enabling multiplanar reformats of equal quality in any plane.

Question 178: A traveling radiologic technologist wants to maximize placement opportunities across the country. Which credential most broadly enhances CT assignment eligibility?

A vendor training certificate from a single CT manufacturer
State-specific CT operator permit from one state only
A local hospital's internal CT competency checklist
ARRT CT post-primary certification recognized by travel staffing agencies nationwide (Correct answer)

Correct answer: ARRT CT post-primary certification recognized by travel staffing agencies nationwide

Travel staffing agencies and their client facilities consistently recognize ARRT CT certification as the standard credential for CT assignment eligibility across the US.

Question 179: CT perfusion imaging requires specialized post-processing to generate which type of parametric maps?

Standardized uptake value (SUV) maps
Bone mineral density scores
Hounsfield unit histograms
Cerebral blood flow, cerebral blood volume, and mean transit time maps (Correct answer)

Correct answer: Cerebral blood flow, cerebral blood volume, and mean transit time maps

CT perfusion post-processing applies deconvolution or maximum slope models to time-attenuation curves to produce quantitative maps of CBF, CBV, and MTT.

Question 180: What is the NATO phonetic alphabet letter for 'B'?

Boy
Baker
Bravo (Correct answer)
Beta

Correct answer: Bravo

In the NATO phonetic alphabet, 'B' is represented by 'Bravo.' This ensures clear radio communication.

Question 181: What is the minimum number of Category A CE credits that must be completed in the final year of a 2-year ARRT renewal cycle?

0 — credits can all be earned in one year (Correct answer)
All 24 credits must be earned evenly each year
12 credits minimum in the second year
6 credits minimum per year are required

Correct answer: 0 — credits can all be earned in one year

ARRT does not require credits to be distributed evenly across both years; all 24 Category A credits can technically be earned at any point during the 2-year cycle.

Question 182: The primary interaction of diagnostic x-ray photons with soft tissue in CT is:

Photoelectric effect
Pair production
Coherent (Rayleigh) scattering
Compton scattering (Correct answer)

Correct answer: Compton scattering

At the diagnostic energy range used in CT (typically 80–140 kVp), Compton scattering is the dominant interaction in soft tissue.

Question 183: When evaluating a CT image for streak artifacts emanating from a hip prosthesis, the BEST corrective technique is:

Increasing the kVp to 140
Decreasing the mAs by 50%
Metal artifact reduction (MAR) reconstruction algorithm (Correct answer)
Widening the reconstruction FOV

Correct answer: Metal artifact reduction (MAR) reconstruction algorithm

Metal artifact reduction algorithms use iterative or sinogram-based techniques to model and subtract metal-induced streaks from the image.

Question 184: A candidate who completed a structured education program in radiologic technology but has not yet passed their primary certification exam may:

Apply for CT if supervised by a radiologist
Apply for CT immediately after graduation
Apply for CT under a provisional license
Not apply for CT until the primary credential is active and unrestricted (Correct answer)

Correct answer: Not apply for CT until the primary credential is active and unrestricted

Candidates must hold an active, unrestricted primary credential before applying for the CT post-primary examination.

Question 185: A patient taking metformin for type 2 diabetes is receiving IV iodinated contrast. Per ACR guidelines, when should metformin be withheld after contrast administration in a patient with normal renal function?

Withhold for 72 hours regardless of renal function
It does not need to be withheld in patients with normal renal function (Correct answer)
Withhold only if the patient has an allergic reaction
Withhold for 24 hours before and after the exam

Correct answer: It does not need to be withheld in patients with normal renal function

ACR guidelines state that patients with normal renal function (eGFR ≥ 30) receiving IV contrast do not need to withhold metformin.

Question 186: A CT technologist retires and allows their ARRT registration to expire for 8 years, then wishes to return to practice. What is required?

A letter of recommendation from a radiologist
Completion of 24 CE credits and a reinstatement fee
Retaking the ARRT CT certification examination (Correct answer)
Submission of a reinstatement fee only

Correct answer: Retaking the ARRT CT certification examination

After an extended lapse beyond ARRT's reinstatement window, technologists are typically required to retake the certification examination to demonstrate current competency.

Question 187: Which professional organization administers the ARRT CT certification examination?

American Society of Radiologic Technologists
American College of Radiology
American Registry of Radiologic Technologists (Correct answer)
Society of Computed Tomography

Correct answer: American Registry of Radiologic Technologists

The ARRT is the credentialing body that administers the CT certification exam for radiologic technologists.

Question 188: Which of the following is the correct order of the surgical hand-scrub process?

Remove jewelry, scrub hands and forearms with antiseptic, rinse from fingers to elbows, dry, don gloves (Correct answer)
Rinse, apply antiseptic, scrub hands, don gloves while wet
Don gloves, scrub hands, rinse, dry
Wash with soap, apply sterile gloves, perform exam

Correct answer: Remove jewelry, scrub hands and forearms with antiseptic, rinse from fingers to elbows, dry, don gloves

Proper surgical scrub progresses from fingers to elbows, rinsing in the same direction to move microbes away from the hands rather than toward them.

Question 189: Under the ARRT primary pathway, how must a Nuclear Medicine Technology (N) credential holder demonstrate CT clinical competency?

By passing only the written CT exam without clinical requirements
By substituting nuclear medicine competencies for CT competencies
By completing an online simulation module
By completing CT-specific competency tasks under the supervision of a qualified supervisor (Correct answer)

Correct answer: By completing CT-specific competency tasks under the supervision of a qualified supervisor

Regardless of primary credential, all CT candidates must complete designated CT clinical competencies under appropriate supervision.

Question 190: What is the ALARA principle in radiation safety?

As Low As Reasonably Achievable — minimize radiation exposure (Correct answer)
Always Lock And Restrict Access
All Labs And Rooms Assessed
Automated Limiting Adjustment for Radiation Applications

Correct answer: As Low As Reasonably Achievable — minimize radiation exposure

ALARA means keeping radiation doses as low as reasonably achievable while still obtaining diagnostic-quality images, balancing benefit against risk.

Question 191: Which technique is most commonly used to reduce metal artifact in CT imaging of patients with hip prostheses?

Metal artifact reduction (MAR) software (Correct answer)
Increasing slice thickness
Decreasing kVp
Using a smaller FOV

Correct answer: Metal artifact reduction (MAR) software

Metal artifact reduction (MAR) algorithms replace corrupted projection data near metal with interpolated data, significantly reducing streaking artifacts.

Question 192: Aliasing artifacts in CT, which appear as fine streaks or Moiré patterns, are caused by which factor?

Excessive patient size
High kVp settings
Insufficient detector sampling (Correct answer)
Incorrect table speed

Correct answer: Insufficient detector sampling

Aliasing artifacts occur when the object being imaged contains spatial frequencies higher than the detector sampling rate can capture, per the Nyquist theorem.

Question 193: On axial brain CT, the internal capsule is bounded medially by which structure?

Caudate nucleus (Correct answer)
Globus pallidus
Thalamus
Putamen

Correct answer: Caudate nucleus

The anterior limb of the internal capsule is bounded medially by the head of the caudate nucleus.

Question 194: Cardiac motion artifacts on coronary CT angiography are primarily reduced by which technique?

Using maximum mAs
Administering iodinated contrast slowly
ECG gating to synchronize data acquisition with the cardiac cycle (Correct answer)
High-pitch helical scanning only

Correct answer: ECG gating to synchronize data acquisition with the cardiac cycle

ECG gating synchronizes CT data acquisition to the relatively motion-free phases of the cardiac cycle (typically mid-diastole), reducing coronary motion artifact.

ARRT Computed Tomography (CT) Certification Examination

The ARRT CT certification exam assesses entry-level knowledge and cognitive skills required for computed tomography practice, covering patient care, radiation safety, image production, and CT imaging procedures across all major anatomical regions.

195

Questions

180 min

Time Limit

75%

To Pass

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